Process for the purification and crystallisation of iopamidol

摘要

The present invention describes a process for the purification and crystallisation of lopamidol, wherein 1-propanol, or 2-propanol, is added to an aqueous solution of lopamidol followed, if necessary, by azeotropic distillation to reduce the quantity of water in relation to the quantity of propanol, and thereby ensure an high yield. The aqueous solution can be prepared either by the dissolution of crude lopamidol in water or directly from the reaction in which the lopamidol is formed. The present invention presents advantages for the routine production of lopamidol since the crystallisation is straighfforward to perform, can be easily controlled and is reproducible at an industrial scale.